Cook penne rigate to al dente (10 to 11 minutes). Reserve 1 cup pasta water before draining.
Season and cook chicken cubes in olive oil, 4 to 5 minutes per side until golden. Remove and set aside.
In the same pan, render diced pancetta over medium heat for 4 to 5 minutes until lightly crisped. Leave all fat in the pan.
Add shallots, cook 2 to 3 minutes. Add garlic, stir 60 seconds. Add tomato paste, cook 2 minutes until darkened. Add red pepper flakes.
Deglaze with vodka, stir 90 seconds. Add tomato puree and simmer on medium-low for 10 full minutes.
Pour in heavy cream, simmer 5 minutes until sauce thickens and turns terracotta orange.
Reduce to lowest heat. Add block-shredded Fontina in 3 to 4 small batches, stirring between each. Stir in Parmesan and butter. Taste and adjust seasoning. Add drained penne and chicken to the sauce. Toss with tongs 60 to 90 seconds until fully coated. Add pasta water one tablespoon at a time if needed. Fry dry basil leaves in hot neutral oil 10 to 15 seconds per batch. Drain on paper towels.
Plate pasta, top with fried basil, extra Parmesan, red pepper flakes, and olive oil drizzle. Serve immediately.